This invention relates to inhibiting distillate fuel oil fouling, manifested by color degradation, particulate formation and gum generation in distillate fuel oils.
During hydrocarbon processing, transportation and storage, the hydrocarbons deteriorate, particularly when subjected to elevated temperatures. The deterioration usually results in the formation of sediment, sludge, or gum and can manifest itself visibly by color deterioration. Sediment, sludge, or gum formation may cause clotting of the equipment or fouling of processing equipment, such as, for example, heat exchangers, compressors, furnaces, reactors and distillation systems. The fouling can be caused by the gradual accumulation of high molecular weight polymeric material on the inside surfaces of the equipment. As fouling continues, the efficiency of the operation associated with hydrocarbon processing equipment, such as heat exchangers, compressors, furnaces, reactors and distillation systems, decreases. The distillate streams which can result in significant fouling include the straight run distillates (kerosene, diesel, jet), naphthas, catalytic cracker feedstocks (gas oils), light and heavy cycle oils, coker naphthas, residual fuel oils, petrochemical plant feedstocks, and hydrotreated products of the above.
It is has been found that some types of color degradation, particulate formation and gum generation can be traced to the presence of indole species and certain phenol species in the fuel oils. It is believed that these species react and cause degradation of the fuel oil. Therefore, it is desirable to develop methods for preventing the reactions of these species and thus the degradation of the fuel oil.